View Compilation Error

0_0_29296257_19589.cpp: In function 'int main()':
0_0_29296257_19589.cpp:25:19: error: 'strlen' was not declared in this scope
   int len=strlen(s);
                   ^
0_0_29296257_19589.cpp:38:31: error: 'strcpy' was not declared in this scope
      strcpy(na[++num].str,str1);
                               ^